This Works for Most Pillar Candles:

If the candle makers do their part right, they've found the best size wick for the diameter of each candle. Before lighting your candle, make sure it is on a stable non-combustable surface. Make sure your candle is clear of anything burnable, above and around. Trim the wick to a quarter inch. This is a good size for most candles(sometimes less, sometimes more).

Once lit, try to put out the flame before the pool of melted wax reaches the edge and starts to drip. Dripping wax can look nice, but it's also the fuel for the flame that's dripping away. Wait for the wax to cool and form a well before relighting the candle.

With all burning candles; if you see black carbon coming off the top of the flame; it is time to put the candle out and trim the wick(quarter inch or less).

Keep your candles free of wind whenever possible; they'll burn longer.